An independent minister and teacher, William was the second son of John Griffiths (1731-1811). He was educated at the school of one Mr. Foyle, at his father’s school, and at Haverfordwest, Wales. He was admitted to the Wrexham Academy February 2, 1795, and was an assistant there in his last year.

Griffiths was ordained as joint minister with his father around 1803. He achieved some degree of prominence as a preacher in English and in Welsh. He was seriously ill in 1809, again in 1824, and died the next year. He was very fond of writing and translating hymns, several of which are found in Y Caniedydd Cynulleidfaol Newydd.